This editor lets you manipulate level-sets, in which you can add, remove and modify levels thanks to a mouse-oriented interface (there are also many interesting keyboard shortcuts). The interface is very straightforward: click on the written planches on the left an right parts of the screen to perform the relevant actions, and on the level area to change the bubble color; use the "void" bubble (or right-click) to remove a bubble.

This is Free Software; this software is licensed under the GPL version 2, as published by the Free Software Foundation. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.